String-truing machine



Feb. l2, 1929. l G- N. ENSELE STRING 'mums momma Wig:

- l EaQof/V, Tm/45 www @ff/777, im wwf@ t Feb. 12, 1929. 1,701,913 G.' N. INSELE ASTRING TRING MACHINE Filed v11911 l. 192e 5 Sheets-Sheet 2 v G. N, EINSELE,

STRING TRUING MACHINE Filed May l. 1926 3 Sheets-Sheet 5 etented Feb. l2, i929,

UNITED STATES GEORGE NICHOLAS EINSELE, v(PIF CEDAR LAKE, INDIAN-A.

.Application filed May ll,

lhis invention relates to string-trailing inachines and relatesparticularly to stringtruing* machines adapted to grind or cut a plurality ot strings ot' various diameters, reducing each string an equal amount, and producingl a uniform thickness. throughout its length.

Strings for musical instruments and the like are connnonly manufactured trom guts? and in their raw condition these guts are rough and irregular and or varying thiol:- ness throughout their length. ln order to obtain'the best results from a stringed instrument, so far as tonal qualities are concerned, the strings must be smooth and uniform in diaineter, or true. Also.. since these strings are of various lengths ranging from 36 inches to over eight feet, depending upon the-instrument in which they are to be used, the machine is adapted to be adjustable to` any desired length ot string. i

@ne oli the objects olthisinvention is to provide a string-truing machine in which. a plurality of strings ot varying dianieter may be around simultaneously.

Another obj ect oit this invention is to provide an improved. automatically controlled string-trump; machine. A c

A 'further object of this invention is to provide a stringstruinp machine in which strings o'l 'various lengths may be trued.

il. further object is to provide a stri,ngtru ina' machine which will turn out work rapidly.

A further object is to provide a string-truingr machinel which will be durablevand etlicient.

Further objects and advantages will be apparent from the drawing when read in connection with the following description, in which drawings Y Figure l is a top plan view of the stringtruing' machine in` which parts have been broken away; I

Fig'. 2 is a side elevational view ott l;

, Fia'. 3 is an enlarged top plan viewot the carriage structure; l

Figi. el. is a section on the line Ll if of Fig. 3

Fig. 5 is a section on the line`5-5 .ot Fia'. 3; i

Fifi. 6 isa section onY the line (3-6 of Fin'.

3; and I l llifr. 7 is a top plan section onthe line 7m? or Fig. 4.

laas. sensi no. roeier.

Referring tothe drawings, and particularly to Figs. l and 2 thereoita supporting structure l0 is shown havingan adjustable headstoclr ll. and an adjustable tailstocltlQ mounted thereon. A plurality ot' revolving centers, or arbore, 13 and le are mounted in the heads stock 1l and the tailstoclr l2 respectively loe.- tween which centers are suspended strings l5. Journalled in said head and tailstoclrs, and extending the full length of the machine to an end support 16, are a pair of traclrsili'A preferably formed of piping, and upon said tracks-a carriage 18 is mounted between the head and tailstoclrs. This carriage carries cut-ting' ele-ments, havingabrading surfaces, and moves longitudinally in a. reciprocating manner along' the tracks ll'. A; cross-head `structure 19 is mounted on one end of the tracks 17 and is connected to the carriage by means oi the rods 20.

Movement is imparted to the cross-head 19 bymeans of a connecting rod` 2l fastened thereto and extendingI to a iiywvheel 22, which latter is mounted on a shatEL in bearings 23 on the supporting structure l0. The flywheel is connected to ,a suitablesource of power by means oit' a belt 24. The drivingmeans just described provide a smooth and somewhat cushioned travel of the carriagea inasmuch as the rate of speed ofthe carriage gradually increases and decreases at the beginning' and toward the end respectively of the travel of the carriage` in either direction. A Y Y Also, the cut to be taken on the string by the abrading` surfaces is so small, perhaps 1/1000 of an inch, that Werethe connecting rodQl directly connected to the carriage, any tendency to bind or tilt the carriage, such as at the Vbeginningl of the stroke, might result in an uneven cut and7 therefore, be detrimental to the effect of the machine on the strings. Therefore, it is the best practice to have the connecting rod indirectly associated with the carriage by means of the .cross-head 19 and the tie-rods 20, as hereinbeiore described.

The. tailstock l2 comprises a U-shaped structure secured to the supporting structure l0 by means oit bolts 25 projecting through slots 26. A pair et projections 27, preferably formed integral with the tailstoclr,V also projectthrough slots 26 and carry a pair of racks Q8 suit-ably mounted thereon for enlil foreign matter collect in said depressions, the positioningof the blocks would not be af- `fected.

The upper frame member 53 comp 'ises a frame member adapted to receive a plurality of upper blocks 69 and has a recess 70 on itsl opposite sides to receive projections 7l of the blocks 59. The only function of the recesses and tlie projection-i thus provided is to prevent the blocks from falling through the opening, and this construction does not, therefore, limit the travel ofthe blocks in any other manner. ln order te prevent the blocks from falling out when the frame member is in a tilted-back-position7 a pair of overlapping' meta-l strips 72 are provided and secured to the frame' member 53 by means of screws 73. Slots 7 l are provided in the strips 72 and disposed angularly therein so that, should it be necessary to remove a block, the screws 7 3 are loosened and the strips pulled back thus shifting the overlapping` portion clear of the projections 7l.

The blocks 69 are located directly above the blocks 65 and have their lower surface coated with a suitable abrading; material, as indicated at 7 5. The ends of the lower block may, or may not, be coated with an abrading material, but both ends thereof are slightly tapered. Between the surfaces of the aforementioned two blocks, the strings are located, and, in operation, are rotated rapidly therebetween, while-the entire carriage is travelling in a reciprocating manner over the full length of the string.

An automatically actuated means is provided for lowering the upper set of abrading blocks in order that anA additional cut will be removed from the revolving` strings onthe return travel of the carriage. For loweringl the abradingor upper blocks G9, the upper frame member 53 is provided with inclined lower surfaces 7 6 and rests on the` upper ends ofthree vertical pins 77. A slight movement to the right in the direction of the ineline would cause a slight lowering' of the blocks 69 and thereby produce a deeper cut on the strings; it ispreferable to provide a three-point support, in order to provide for an exact cut', since any irregularities, such as the warping ofthe frame, .would be harmful Yto the operation'of the machine were other supporting means used.

The means for automatically causing` the shift of the upper frame member to produce the deeper cut, as aforesaid, comprises a bellcrank lever 7 8 pivotally mounted on a bracket 79 and secured to the upper frame member. On the return travel of the carriage,cone end ofthe bell-cran`lr lever 7 8 is caused to abut anA an arm 81 which in turn is providedy with a pawl port-ion in engagementfwith a ratchet of the block.

ing surface and to wheel 82,`a further travel beyond the point at which the bell-crank lever` abuts the adjustable screw 80, will cause a movement of the arm 8l and produce a partial rotation of the ratchet wheel 82.

ji. frame 83 is'secured to the upper frame member 53 and has a threaded shaft 84 screwed therein. The ratchet wheel 82 is mounted on shaft 84rbetween the arms of a forked projection 85 and is held in an impositive driving relation with respect to said shaft by means of a spring'washer 86 pressing saidgear against the'shoulder 87. As the gear 82 and the threaded shaft 84 are rot-ated, the shaft is held from `endwise travel by means ofthe forked projection and, therefore, the frame 83 causes the upper frame member 53 to move' in one direction or the other. in adjust-able stopV 88 is secured to a kprojection 89 on the lower frame member to regulate the distance of the travel ofV For thispurposean arm 90 is provided on each block, and at the upper end of said arm a pin 9i extends through to the exact width A set` screw 92 is provided on a supporting' structure* 93 in approximate alignment with the pins 9i.l A screw 94, having a hand wheel 95,*is provided on the oppo site side of the set screw 92 and is journalled in the supporting structure 93 at a point near 'the lower end ofthe projecting arms 90. Each of theblocks 69isprovided with4 an arcuate surfaceon one `side thereof and a straight side on the opposite side, each adjacent block having its arcuate side abutting` the straight side of the other. This acts as a `preventative against any foreign substance niisaligning the blocflrs in addition to providing a more efiicient bearing` surface. hand wheel 95 is .tightened :so that the screw 9st presses against the iirst block which action is carried through the blocks and against the set screw 92. rlhe blocks are thus held in any desirable position, and as shown clearly in Fig. 6 of the drawings, the diameters of the strings may be of any size.

ln order not to cut a groove in the abradge the use of the full width thereof, the lower frame member 52 is supporting structure 5l. This movement is effected by a screw member 96 having a screw threaded engagement `with the structure. 51 and having a swivel connection with the lower :trame member 52. ated manually or automatically. VThe automatic. means `provided for in this instance The lll)

`This may be operiso V"comprise tivo ratchet'u'heels 97 and 98 moiinted, on the screw .member 96 and :having their teetlicut in dirti'erent directions, asY shownV more particularly in Fig. 5 of the dravvings.V

A duplex paivl 99 is pivotally mounted on theuppertramemember 53 and is provided With'hook members 100 andrlO, each'oit'the latter lying in the plane of its respective ratchet-member 9701 98. Uponthe lifting of the upper frame member 53, the hook 101 engages'ay tooth of the ratchet 98 and rotates the screw 96 in one direction to move the frame'membcrs 52 and in order that a fresh surface be provided igor the string` llV Simi ilarly, if the pawl99 is pivoted to a position on thev reverse side of the ratchet members, ther hook 100 engages a tooth of the ratchet 97 and rotates the screw -96 in the opposite direction. A pin' 102 is provided to hold the paWl in an off-center position in either instance, in orderL that the pavvl will be forced outvvardlyby the ratchet Wheels when the upper frame member is assumingits normal position on the strings` This is, ot course, but one of several means that may b e provided -t'or by automatically adjusting the abrading surtt'aces so that the fiillwvidth thereof maybe .utilized and this invention'is not, therefore,

t'o'be limited to this means solely.

In'the operationV of the machine, a plii-` 'rality otstrings are-suspended betweenthe revolving centers 13 and lt.' Thevcarriage,

carrying aY plurality of; pairs of* yieldingly mounted aloradinc` blocks, between. which the strings are rapidly rotated, isV moved along 'thistraclrin a reciprocating manner and longitudin'ally i ot the., 1 strings.. OnV the Y' return travel ofthe carriage, the distance .between theV abrading blocks is slightly reduced and a new cutis inadeonithe Strings. i `This op- .eration is continued until the 'upper `trame member abuts the' stop 8 8 Which predeterminesthe amountof cut to taken'on the strings. The upper framememherl is vthen liftedV clear'ot the strings'and thestrings are rr'emoved Vand' a new/supply of stringsrplaced betuieentlie centers.

In supplying a fresh supply of strings to "I the machine. the hand Wheel 95 is loosened lce Y (vided. Qne'set is fixed to each'sideof thesup- .Y `porting structure for steadying the strings 'at points nearthe abrading surfaces, While andthe :blocks 69 Vare allowed to rest .on` the strings independently of each other, and, as shown in. Fig. 6,'various diametersof strings -inay'beA accommodated. The' hand Wheel 95 is then Vtightened.and tl'iermachi'neis rea-dy torfopei'ation.)It is obvious that the same amount of cut Will be talenrfrom eachstrmg and that any irregularities in the diameterA ot the string Will be remedied; however, .any undue pressure isfcreated, the coil springsA Vii'iillpermit the lower blocks @5to yield and therebyrelieve the pressure.

@Tufo sets of notched 'anges l03are pro-y string 5 during rotation lthereoji", means thev strings are placed infthese `notches respec-i tively and steadied ,therein as they revolve'.y

In order to adjust the -yvidthrof the notcheach set Yot flanges comprises: two, members, the outer member being shittable to varythe As, aresultot this invention, it is possible to simultaneously true a plurality ot strings having various ydiameters it is; alsoV possible to adjust the travel of' the carriage4 andthe .effective Width ot the notch Vinthe adjacent means Yfor suspending the strings'to accome inodate the various lengthsl demanded by the different instruments5it ispossibleto turn out 4the Work rapidlyyandaccurately, and,

Vso' nally, the device is automatically operatedV `which perinitsof its ,being operalt'edby unskilled laborthereby. reducing the cost of the V y resultant product to ai minimum.

While a single embodiment or' this invention is herein shown and described,git is tobe understood vrthat this inventionjisrnot to be limited to Ythat speciiicstructure, since many modiiications may be apparent? to Y those skilied in the art Without rdepartingfrom the spirit of the inventioiniand Idesire, therefore, V that the same be limited only by the scope f of the appended claims and the'priorc art. Y l

tclaim:V y' LVA string truing machine comprising means for rotating astiing about an axis eX- tending longitudinally ot' the string,f a non- Y rotatable cutting lelementiltor engaging said for effecting relative movementV between' said string and cutting. elementlin'a` direction longitudinally ofthe string, and -yieldable sup Vporemgfmeans opposite said cuttingelement for holding said Vstriiig againstysaid cutting element. Y i i l y 2. A string truing' 1nachine..comprising Ameans for rotating a string about an axis eX- Y tending longitudinally "ofthe string, ia'non- Y Y rotatable `cutting element foriengag'ing `said stringrlurmg rotation thereof, means-for effecting relativel VmovementVV between vsaid string and cuttingelement in; af direction loniio gitudinally of thestring, supporting means' opposite said cutting element forholdingisaid string against said Cutting element, and

'means tor holding saidsupportingmeansa predetermined distance trom said cutting element as the string is rotated todetermine the Y depth1 of cut. 'Y c 3. string truing-machine comprising] means foifrotating a string vaboutan axis means opposite'said cutting element lfor holding saidv string againstsaid'cutting element, and Ameans for yieldingly holding` said supporting means a pre-determined distance from said cutting element .as the string is rotated to determine the depth of cut.

l. A string truing machine comprising means for holding `a plurality of strings substantially parallel to each other, and rotating them about their axes, cutting means for engaging said strings during rotation thereof, and means for effecting relative movement between said strings and said cutting means in audirection longitudinally of the strings, said cutting means comprising a plurality of adjustable cutting elements, one for each string.

5. A string truing machine comprising means for holding a plurality of strings substantially parallel to each other, and rotating them about their axes, cutting means for engaging saidfstrings during rotation thereof,

and means for effecting relative movement between said strings and said cutting means in a direction longitudinally of ythe strings, said cutting means `comprising a plurality of cutting elements, one for each string, andsupportingmeans comprising a plurality of supports, one for each cutting element for holding said strings yagainst said cutting elements.

G. A string truing machine comprising means for holding a plurality of strings substantially parallel to eachother, Vand rotating them about their axes, cutting means for engaging said strings during rotation thereoi, and means for effecting relative movement between saidstrings and said cutting means in a direction longitudinally of the strings, said cutting means comprising a plurality of cutting elements, one for each string, and said supporting means comprising a plurality of supports, one for each cuttingelement for holding said stringsagainst said cutting elements, each-cutting element and its support being relatively adjustable, independently rof the others, to enable strings of different thicknesses to be simultaneously operated on.

7. A string truing machine comprising means for `holding a plurality of strings .substantially parallel to each other, and rotating `them about their aires, cutting means for engaging said strings during rotation thereof, and means for eifecting relative movement Ibetween said strings and said ycutting means in a direction longitudinally of the strings, said cutting means comprising a plurality of cutting elements and means whereby said vcutting elements may be adjusted independently to operate on strings of dilferent thicknesses, and may be adjusted collectively With respect to the strings in adjusting for a cut.

8. A string truing machine comprising means for holding a plurality of strings substantially parallel -to each other, and rotating `them about their aires, cutting means tor engaging said strings during rotation thereof, and means for effecting relative movement between said strings and said cutting means in a direction longitudinally of the strings, said cutting means comprising a plurality of cutting elements and a holder in Which said cutting elements are independently adjustable for operation on strings of di'lferent thicknesses.

9. A string truing machine comprising means for holding a plurality of strings substantially parallel to each other, and rotating them about their axes, cutting means for engaging said strings during rotation thereof, and means for eifecting relative movement between said strings and said cut-` ting means in a direction longitudinally of the strings, said cutting means comprising a plurality of cutting elements and a holder in `which said cutting elements are independently adjustable for operation on strings of different thicknesses, said holder being adjustable with respect to said strings to adjust the cutting elements collectively With respect to the strings in adjusting for a cut.

1.0. A string truing machine comprising `means for holding a plurality of strings substantially parallel to each other, and Vrotating' them about their axes, cutting meansfor engaging said strings `duringrotation thereof, and means for eifecting relative nievement between said strings and said cutting means in a direction longitudinally of the strings, said cutting means comprisinga plurality of elongated non-rotatable cutting elements, one for each string, extending longitudinally of the strings. l

l1. A string truing machine comprising means for holding a plurality of strings substantially parallel to each other, and rotating them about their axes, cutting means for `engagjng said strings during rotation thereof, and means for eifecting relative movement between said strings and said cutting means in .a direction longitudinally of the strings, said cutting means comprising a plurality of cutting .elements and a holder in which said Vcutting elements kare independently adjustable for operation on strings of different thicknesses, said holding means being provided with means for .clamping the cutting elements in their adjusted positions.

12. A string truing machine comprising means for holding a plurality of stringssubstantially parallel toeach other, and rotating them `about their axes, cutting means for engaging said strings during rotation thereof, and means for effecting relative movement bet-Ween said strings and .said cutting means in a direction longitudinally of the strings, said cutting means comprising a plurality of cutting elements and a holder inwhich said cutting elements are independently adjustable for operation on strings of different thicknesses, said holding means being provided With means for clamping the cutting elements in their .adjusted positions, said holder being adjustable `With respect to said Y Vstrings to adjust the cutting elements col-i i inl lectively with respectto vthe strings in adjustiiig forcut. y Y f i 13. stringtruingV machine comprising means for'holding a plurality of strings substantially parallel-to each other, and rotating v'them about their axes, cutting means for engaging said strings 'during rotationVV thereof, and means for effecting relative movement between said stringsand sai'd'ci. ting' means fina direction.-longitudinally of thestrings,

saidjcutting means comprising a plurality of'cutting 'elements 4and a holder Vin which said,` cuttingjelements are independently instable for operation on stringsof different thicknesses, said holding vmeans beingwpro-` vided `with means for clampingv the cutting elements in their adjustedpositions, said Vcutting elements having line contacts with each 4other when clamped together: v y' f `14. A string truing machine comprising means for rotating a string about an axisY eX- tending longitudinally of the string, anonw rotatable cuttingelement for engaging said stringduring rotation thereof, means for effectingl relative movement V between 'saidy tingelement in a direction longitudinally of Vthe `string, supporting meaiis'opposite said cutting element `for holding said. string against said rcutting element, and ineansY controlled automatically bythe relative longitudinalniovement between the string and cutting element for varying the distance be- Vmeans in adjusting for a cut. 1116. A string truing machine comprising tween the cutting` element and supporting 'means for rotating a string about an axis eX- ftending 'longitudinally of the string, cutting element for engaging said string during rotation thereof, Ymeans for effecting relative movement between said .string and cutting elementin a 'direction longitudinallyof the string, supporting means opposite said cuttingelement for holding said string against said cutting element, and means for varying "the .distance between said cutting element and lsupporting means in adjusting for a cut, coinrprising a member Yhaving a surface inclined with respect to said string, a member engaging said surface, and means for Aeffecting relative movement between said members.

17; A Y'string truing machine comprising S venais Y means forrotating a string about anaxis ex'- tending; longitudinally ofthe string, a cuttingelement for engaging saidstring during rotation thereof, means for edectin'g relative movement between said string and cutting element in a direction,longitudinally of theV string, supporting inea-ns Vopposite said cutting element for holding said string against said cutting element,and meansv for' varying the distance between said cutting element and supporting means in adjusting fora cut, comprising a member having a vsurface inclined with respect to said string, a member engaging said surface, and means for eifecting relative movement between said members, said last means comprising a screw and yratchet mechanism 1 for operating said screw controlled automatically by the :rela

tiveilongitudinal movement between said ciitting element and strinv. w

18. Af'string `truing machine comprising means for rotating a string aboutan axis extending longitudinally offthe string,'a Ycutting element for engaging said Vstring during rotation'ther'eof, means for eecting' relative movement between said string and cut- 'Y ting element in a direction longitudinally of the string, supporting means opposite said cutting element for holding said string lagainst said cutting element, and means for automatically varyingthe distance between said cutting element and vsupporting means in adjusting-for a,cut,lcomprising a screw and ratchet mechanism fori-operating said screw controlled by the relative longitudinal movement between said cutting element and string.V

,"19,V A string truing machine comprising means for rotating a string about an axis eX- tending longitudinally of the string, a cutting element for engaging said string during rotation thereof, means for effecting relative Vmovement between said string and cutting elementY in a direction longitudinally lof the Y string,supporting 'means opposite said cutting element 'for holding said string against said cutting element, andl'means for auto-` Vmati'cally varying the distance between said cutting element and'sfupp'orting means in adjusting for a cut, comprising a ratchet mechanism `controlled by the relative longitudinal movement between said cutting element and string. f f Y Y 20.A VAustring truing machine comprising means for rotating'astring about an axis eX- tending longitudinally of thestring, a cutting element for engaging said string during rotation thereof, meansfor eecting relative movement between said string and cutting element in a .direction longitudinally ofA the string, and means for adjusting said cutting element laterally of the string in order4 to utilize the entire cutting surface of said cutting element, a holder on which said cutting element is mounted for movement lto- `iio y momie Ward and from the string, and means ControlledV by movement of said holder for effecting the lateral adjustment of the Cutting element.

2l. A string truing machine comprising means tor rotating` a string about an axis eX- tending longitudinally of the stringya cutting element for engaging said string during rotation thereof, means for effecting relative movement between said string and cutting element in a direction longitudinally of the string, supporting means opposite said eutting element for holding said string against said Cutting element, and means for varying the distance between said cutting element and supporting means in adjusting for a eut, comprising a member having` a surface in-V clined with respect to said string, a threepoint support for engaging said surface, and means for effecting relative movement between said member and said three-point support. Y

In Witness whereof, I have hereunto subscribed my name.

GEORGE NICHOLAS EINSELE. 

